Transcript Document

Cockayne
syndrome
Background:
Cockayne syndrome:
is a rare and devastating genetic disease. It is
present in about 1/100,000 live births. Its
inheritance is autosomal recessive. In other
words, it occurs if both the father and the
mother pass on a damaged gene to the
affected child, with the parents themselves
having no health problems related to CS, and
with 1/4 of the siblings expected to also have
CS.
Type:
CS type 1 (CS-A or CKN1):
the classic form
CS type 2 (CS-B ):
a more severe form with symptoms
present at birth
CS type 3:
a milder form
xeroderma pigmentosa–Cockayne
syndrome (XP-CS)
How to Diagnose (诊断)CS
within the first 2 years of life,
growth and development become
abnormal.
By the time the disease has
fully manifested, height, weight,
and head circumference are far
below the fifth percentile.
The characteristic physical
appearance of the aging process.
dwarfism(侏儒) with thinning of
the skin and hair, sunken eyes, and
a stooped standing posture
Lifespan
Patients are at risk for postnatal growth failure, pigmentary
retinal degeneration, and premature death before adulthood.
The oldest CS patient known to Share and
Care Cockayne Syndrome Network is in the late
30s. For children born with cataracts, the life
expectancy is 12 years, and many CS patients
die in infancy. Both the severity of the genetic
damage in the individual patient, and the quality
of care including ensuring adequate food intake,
are important determinants of the lifespan.
pathophysiology
Pathologic studies reveal diffuse
and extensive demyelination(脱髓鞘)
in the central and peripheral nervous
systems.
what gene is affected in the CS
patient.
This includes the CS-A gene,
ERCC8 , in about 25% of cases;
and the CS-B gene, ERCC6, in
about 75% of cases.
CKN1
CKN1 is caused by a defect in the CS
type A gene (CSA or ERCC8) located on
chromosome 5.
Affected persons inherit 2 mutant genes,
one from each parent. Cells carrying
ERCC8 mutations are hypersensitive to UV
light. They do not recover the ability to
synthesize RNA after exposure to UV light.
In addition, the cells cannot remove and
degrade DNA lesions from strands that
have active transcription.
Treatment
There is no cure for Cockayne
syndrome, so threatment focuses
on relieving symptoms and
improving the person’s quality of
life. Physical and occupation
therapy can help maintain joint
function and reduce muscle
contractures.
Medical Care:
Treatment of patients with
CKN1 depends solely on the
presenting symptoms. Physical
therapy helps prevent
contractures and helps maintain
ambulation
Activity:
Physical therapy is essential to enable
patients to avoid joint contractures and
to prolong ambulation .
Protect:
protect himself from sunlight with
clothing and sunscreen, to reduce cell
damage.
THE END